so the problem is like this :
If you have 5 trucks wich transports 460 Tons in 12 hours, how much Tons does 7 trucks transport in 11 hours ?
Essentially the same as Subhotosh Khan but different in particulars: The way I approach problems like this is to look to see what is wanted, i.e. how to measure. In this case the measurement is tons per truck-hours so we have the rate r is
r = \(\displaystyle \frac{460\, tons}{7 * 12\, truck-hours}\, =\, \frac{23}{3}\, \frac{tons}{truck-hours}\)
Suppose we have 3 trucks. What can they move? Well
3 trucks * r = \(\displaystyle 3\, trucks\, \frac{23}{3}\, \frac{tons}{truck-hours}\, =\, 23\, \frac{tons}{hour}\)
so they can move 23 tons per hour.
What if I had 7 trucks for 11 hours, i.e. 77 truck-hours. What can they move?
BTW: Notice that you could turn this upside down also to get a truck-hours per ton
R = \(\displaystyle \frac{3}{23}\, \frac{truck-hours}{ton}\)
so if you wanted to move 23 tons you have 23 R and would need 3 truck-hours, i.e. 3 trucks for 1 hours or 1 truck for 3 hours or ...
